Beta Test emonSD-13Jun18 Stretch Image on Raspberry Pi 2B

My Raspberry Pi 2B failed to boot this beta image; stuck part way through. Took me a while to track down the problem: config.txt file in the image specifies arm_freg 1200 - 2B; Pi2B will not run at that speed. Commented out those arm_freq lines, now running.

For me it troubleshooting was complicated as I used new SD card, and suspected that, first time with Etcher, suspected that, image has multiple partitions, that was confusing, and I usually set up SD to enable SSH with ssh file in boot, so did not have HDMI console to see what was going on. And I believed you when you said image was back compatible :slight_smile: Not sure why you added the arm_freq, as I think those are the defaults for Pi3B anyway?


Hi John,

Indeed they are. The Pi 2B clock speed should be 900 MHz.

@glyn.hudson sounds like the code needs “model detection” or
if it already can detect which Pi it’s running on, it needs to be fixed.

The model is definitely detected by the normal RPi boot process, and I believe the arm freq is set from that as “default”. I think the arm_freq entries in the config.txt are mostly for overclocking or special applications.

Correct. Normally nothing need be done to get a Pi to use the correct clock speed.
You might want to have a look at this:

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Thanks for reporting this issue. The emonSD-13June18 is still in Beta. I will add this onto the list of things to fix before we release.

Thanks again.

The new image is targeting the 3B+ which has the same processor has the Pi3 but overclocked from 1.2Ghz (on Pi3) to 1.4Ghz (on 3B+)


have been added to the boot/config.txt to set the 3B+ clock frequency back to the non-over clocked speed of 1.2Ghz. This is done since the emonPi application does not significantly benefit from the extra clock speed. Lower clock speed will mean better temperature and voltage tolerance and longer lifespan as well as lower energy consumption. Users can removed these lines if extra horse power is required.

The new image due to be released soon (emonSD-18Oct18) will contain these lines in boot.txt therefore won’t work out of the box with Pi2. If using on a Pi2 you will need to edit config.txt to remove these lines. I don’t think there is a way within config.txt to detect Pi version. However, we don’t see this being a big issue since most users will be using Pi3 or above to benefit from the built in WiFi.

Here is the default config.txt as used on the new Stretch image:

Has the new image release being delayed? Couldn’t see it on github wiki page.

I was using the emonSD-13Jun18 Beta without any issues but SD card seems to have packed up, so need to start again, thought I may as well wait a bit if there was a new release coming.

The image is now released!

Sorry, took a bit longer than planned. We ended up completely re-building the image from scratch from a fresh Stretch image since we were not happy with the upgraded image that emonSD-14June18 was based on. I would highly recomend moving to the new image emonSD-30Oct18.